Device for indicating pressure in liquids and gases



May 1s, 1965 H. P. o. UNGER ETAL DEVICE FOR INDICATING PRESSURE INLIQUIDS AND GASES Filed May 22, 1962 ma@ wf @1m/ ma! n .SY M aus y v 9United States Patent O The present invention shows a device forindicating pressure, or variations in pressure, 'in liquids and gases ofsuch properties as for instance viz liquor, blood, pleuroexudate,ascites and pneumothoraxic gases, without thereby causing loss of thementioned medium, as well as enabling the medium to be introduced ordrained '(from the device, upon which a new 'pressure indicating ,may beperformed, without necessitating withdrawal of the device from themedium in question.

The primary purpose of the present device is to enable the execution, bysterile work methods, certain applica- 'tions on the liquids and gasesencased in the human body.

Many currently available designs for Y pressure indicating, based onmechanical or electronic principles,.have in commomvthe vfact that anappreciable amount of the medium is introduced into Vtherecordingsystem, from which sterile recovery is impossible, and which is hereinreferred to as a loss of medium. YThis `may well endanger a patientslife in connection with a pressure indicating or` recording of liquor atpathological pressure conditions. Designs so arranged that this probelmhas been eliminated are of particularly complicated construction, henceinitial cost and maintenance are extremely expensive.

The device for recording pressure according to the invention consists ofa transparent'cylinder, in which is Varranged a mobile rod-pistonassembly. The cylinder is connected through a channel to a nozzle, wherea replaceable puncture needle (channelled') is inserted. The free end ofthis needle may be introduced into the mentioned liquids or gases, whichvia the needle may propagate into the nozzle. The `particularsof thedevice are as follows. The nozzle consists of a transparent materialfabricated tube, which in the lateral direction is furnishedwith atleast one level mark. Furthermore, atleast one pressure unit scale isarranged beside the cylinder or its piston rod, against which the liquidor gas pressure might be indicated, when the liquid'or the gas bydischarge from the encased chamber is brought to reach the level mark inthe nozzle, and retained there by action of the gas or air cushion,created between the 'piston and the needle. This "cushion is the counterpressure medium against the liquid or the gas, whereby the mentionedliquid or gas is prevented from propagating into the cylinder, as wellas Vsecuring its return to the encased chamber.

The device is further characterized by the'U-shaped nozzle design,whereby the channel between the two nozzle ends becomes considerablylonger than a straight line distance between the same. This arrangementis made with the intention of retarding the progress of the gas or theliquid through the nozzle, until the gas or air cushion counter pressurehas been activated.

Two separate designs of the device according to .the invention,Vmodiiications and details inclusive, are described below in connectionwith the annexed drawing wherein.

FiG. l shows a longitudinal section of the device according to the oneofV thetwo designs.

Fifi. 2 shows a view orr the nozzle accordmg to a modified form.

ldflg Patented May 18, i965 ICC FIG. 3 shows a view of the nozzleaccording to a second modified form.

FIG. 4 shows part of the device according to the lsecond design.`

FIG. 5 shows schematically a view of a calibration instrument, intendedto be used in certain cases in connection with the device according tothe invention.

In FIG. 1 the device is shown in vertical position. The cylinder and itssurrounding transparent graduated housing are partly shown in crosssection. A liquid filledl hollow chamber shown at 1 is confined by awall l". The puncture needle is shown at 1 while 2 denotes the nozzlethat is attached to the needle and, which is made from glass and has achannel 2. The level mark or the nozzle adjustment mark is Vrepresentedby 3. The faucet system connected to the nozzle 2 consists of a threewayvalve 4 with its channels 5, 6, and 7. The channel 6 is designed withadequate faucet position to allow drainage of gases or liquids from themedium 1', or from the cylinder 8, subsequent to Vdeliberate aspiration.The vchannel 6 is also intended for feeding liquids or gases to themedium l. The channel 7 is connected to the cylinder '8, housing agastight piston 9. This piston, which may be of such gastight materialas Teflon, is furnished with a Vsurrounding vcoil 10 and a piston rodspring 11.

When a liquid Vof a certain viscosity, for example liquor, penetrates`into the puncture needle V1 and 4enters the nozzle channel 2', a springcounter pressure is applied manually against the piston rod 16.v `Byaction of the gastight piston 9, the air 'in the cylinder`8, as well asthat in the expansion chamber 8', will be compressed. This expansionchamber 3', which may be opened'as well as entirely removed from thedevice, is connected by a channel, in which is installed a valve 8", tothe channel 2' in the nozzle 42. In this way the increase of liquor inthe channel 2 is checked. The manual counter pressure is adjusted insuch a way as to bring the boundary surface between the liquid, i.e. theliquor, and the air to the level mark 3. Thus the piston9, which throughthe action of thepiston rod spring '11 was sithated in its top position,i.e. immediately below the cyl- Ycylinder is surrounded by a transparentrevolving housing l2, furnished with pressure unit scales 13, forinstance in man1-120 or Hg, the pressure can directly be read againstthe scale, using the pistons position in the cylinder 8 as indicator.

FIG. 2 shows the Anozzle 2av in a modified form, characterized by itselongated U-shape and its vbeing furnished with a long channel 16 ofnarrow caliber. This nozzle 2a may be used in'connectionwith recordingthe pressure of liquids of low viscosity, subjected to relatively highpressure conditions. This, because of the progress of the liquid may befollowed visually, enabling the build up of an adequate counter pressurebefore any of the liquid reaches the recording system. Thus, loss of themedium l is effectively prevented.'V v

PIG. 3 shows a second modificationrof the nozzle 2b in operatingposition. channel 5 has such characteristics that attachment can be madeonly when the device is in operating position, i.e., inverticalfposition. Even this nozzle 2b is U-shaped. Its channel 17'is,however, so adjusted that, when used in conjunction with the lcylinder 8and the expansion chamber d', its net volume is greater than the addedair 'volume The nozzle 2b connection to the liquids.

of the mentioned cylinder and expansion chamber under uncharged pressureconditions, i.e., the piston 9 being in its top position (FIG. 1). Thechannel 17 of nozzle 2b is intended to be filled completely with forexample a sterile physiological salt solution. The nozzle constructionresults in the absolute prevention of air from being introduced into themedium 1', because even if the piston 9, accidentally or caused by otherreasons, should be forced to the bottom of the cylinder 8, the trappedair can be forced no farther than to channel 17 in nozzle 2b. Thechannel 17 will, thus, become partly filled with air, While the liquidpresent in the same will be forced to enter the medium 1. Air, however,can never be introduced into the medium 1'. In FIG. 3, a graduated scaleon one of the legs is visualized. This scale enables continualrecordings of pressure variations, subsequent to adjusting theliquid/gas boundary surface at the level mark 3. The nozzle 2a, shown inFIG. 2, may similarly be furnished with the mentioned graduated scale.At pressure recordings where even a diminutive amount of the medium 1(corresponding to the added interior volume of the puncture needle andthe nozzlechannel as far as the level mark) cannot be allowed to leavethe medium 1', the mentioned volume may of course be filled with aliquid as far as the level mark 3, through aspiration with the piston 9or in some other way, before puncture is made.

Fig. 4 shows schematicallya separate design of the piston 9 and thepiston rod 10', where the piston 9 is furnished with a suitable type ofsealing rings to ensure gastightness. The piston rod 10 is furtherdesigned with suitable threads and placed in a threaded housing 14.

YThe counter pressure build up is caused by screwing the piston rod 10downwards.

The piston rod 10 may through jack or something similar in the threadsbe graduated with pressure unit scales 19, thus replacing the graduationdevice represented by the mentioned housing 12. This constructionenables counter pressure build up at particularly high pressures.

The principle in its above described constructionormsY may even beutilized for indicating gas pressure. In this case a small amount ofliquid 1S is introduced into the nozzle before pressure recording, asshown in FIG. 2. This liquid acts as a buffer between the two gases,i.e., between the gas, the pressure of which is to be indicated,

Y and the air (gas) in the indicating system.

The mentioned device and principle is even applicable in the case ofindicating negative pressure in gases or In such case, the initiallymarked position of the piston 9, at commencing indications, is arrangedin the lower part of the cylinder 8. Upward motion of the piston 9during indications will create a negative pressure in the cyliner S andits connected expansion chamber 8. This negative pressure equals thatofthe liquid or the gas, the negative pressure of which is to beindicated, when the liquid boundary surface or the small amount ofliquid 1S respectively have been positioned to the level mark 3. Theposition of the picture 9 in the cylinder 8 is in this case theindicator of the negative pressure in connection with an adequatelycalibrated and gradu'atediV scale on thel housing 12.

In FIG. 5 is shown a simple and adequate calibration instrument for thedescribed pressure indicating device. This instrument consists of aleakproof cylinder, equipped with an inlet, drain, and a manometer, aswell as pressurefv Y Y Due to the fact that principle of therpressureindicating' "70 'Y 1,900,775

device according to the invention is based on an enclosed gas volume,for example, airunder negative or positive pressure, contingencies mustbe made for. variations 1n temperature where stringent prerequisites Yasto measuring v accuracy prevails,.

A variation in temperature of 10 C. will produce a correspondingvariation in gas volume of roughly 3%. Large variations in temperaturemay, thus, lead to small discrepancies in measuring accuracy. Thiseffect is eliminated by separate pressure calibrations for differenttemperature ranges. In connection with medical applications of thedevice, where pressure recordings are performed at room temperature withthe air or gas containing chambers carefully insulated, this effect hasno impact.

The provision of adequate calibration and gastight construction beingensured, this device represents an inexpensive instrument for recordingpressure in liquids and gases, which is easy to handle, assemble, anddismount, as well as sterilize before use. The device is particularlysuited for medical applications under sterile conditions, though it canbe used for a wide variety of industrial purposes as Well.

The invention is not limited to the above described, and in the attacheddrawing clarified, construction forms with modifications, but it can bevaried further in a number of ways, Within the framework of theinvention idea. Examples of this are placing the cylinder and theeXpansion chamber in other locations on the device, as well as usingexpansion chambers of varying interior volume for certain given pressureranges. For industrial applications the puncture needle may be replacedwith a leakproofconnected tube between the medium and the pressurerecording device.

We claim:

Yl. A device for the measurement of the pressure of liquids and/ orgases enclosed in spaces, vessels, or organs isolated from theatmosphere, such as in a human or animal body, said device comprising. atransparent cylinder containing a slidable piston provided with apistonrod, said cylinder having a duct connected to a nozzle providedwith a channel, a puncture needle provided with a channel and beinginterchangeably fitted in said nozzle, an expansion chamber connected tothe connecting duct, the nozzle comprising a tube of transparentmaterial, Said tube being provided with at least one latitudinal levelmark, characterized in that all component parts of the device are ofrigid material and are combined in a rigid unit, a three-way valve, theconnecting duct between the nozzle and the cylinder being connected tosaid three-way valve, which valve is connected to a discharge channel,and the piston-rod being biased by spring means, and that the cylinderis provided with at least one pressure unit graduation.

2. A device according to claim 1, characterized by the fact that thepiston-rod is provided with at least one pressure unit graduation.

3. A device according to claim 1, characterized by the fact that thepiston rod is provided with threads adapted to engage the top of thecylinder.

4. A device according to claim 1, characterized in that Vsaid cylinderis surrounded by a revolving, transparent collar provided with saidpressure unit graduation. 5. A device according to claim l,characterized by the fact that the nozzle is U-shaped, so that thechannel in the nozzle is appreciably longer than the direct distancebetween the ends of the nozzle.

6. A device accordingl to claim 5, characterized in that one leg of theU-shaped nozzle has a greater interior volume than the other leg.

References Cited by the Examiner UNITED STATES PATENTS 3/33 star 73-401X FOREIGN VP/lrnrnrs 830,729 5/38 France.

(Uther references on following page) 3,183,722 5 6 OTHER REFERENCES ofYthe American Medical Association, vo1.'123, No. 2, A SimpleMicromanometer, by E. Kovacic, Journal of Sept- 11 1943' Pages 91 and92' lenatlc 3gijstruments, vol. 30, September 1953, pages RICHARD C.QUEISSER, Primary Examiner.

The Phlebomanometer, by G. E. Burch et a1., Journal ROBERT L. EVANS,Examiner.

1. A DEVICE FOR THE MEASURMENT OF THE PRESSURE OF LIQUIDS AND/OR GASESENCLOSED IN SPACES, VESSELS, OR ORGANS ISOLATED FROM THE ATMOSPHERE,SUCH AS IN A HUMAN OR ANIMAL BODY, SAID DEVICE COMPRISING A TRANSPARENTCYLINDER CONTAINING A SLIDABLE PISTON PROVIDED WITH A PISTONROD, SAIDCYLINDER HAVING A DUCH CONNECTED TO A NOZZLE PROVIDED WITH A CHANNEL, APUNCTURE NEEDLE PROVIDED WITH A CHANNEL AND BEING INTERCHANGEABLY FITTEDIN SAID NOZZLE, AN EXPANSION CHAMBER CONNECTED TO THE CONNECTING DUCT,THE NOZZLE COMPRISING A TUBE OF TRANSPARENT MATERIAL, SAID TUBE BEINGPROVIDED WITH AT LEAST ONE LATITUDINAL LEVEL MARK, CHARACTERIZED IN THATALL COMPONENT PARTS OF THE DEVICE ARE RIGID MATERIAL AND ARE COMBINED INA RIGID UNIT, A THREE-WAY VALVE, THE CONNECTING DUCT BETWEEN THE NOZZLEAND THE CYLINDER BEING CONNECTED TO SAID THREE-WAY VALVE, WHICH VALVE ISCONNECTED TO A DISCHARGE CHANNEL, THAT THE CYLINDER IS PROVIDED WITH ATLEAST ONE PRESSURE AND THE PISTON-ROD BEING BIASED BY SPRING MEANS, ANDUNIT GRADUATION.